(a) Field of Invention
The invention relates to an electronic system for preparing portions of food in a plurality of microwave ovens. More specifically, the invention relates to such an electronic system wherein the plurality of ovens are controlled from a central source. The invention also relates to a method of preparing portions of food in a plurality of microwave ovens using the said electronic system.
(b) Description of Prior Art
Microwave ovens are known in the art. Electronic controls for individual microwave ovens are also known in the art. However, different foods, depending on the nature and state of preparation of the portion to be processed in the microwave oven, and also depending on the mass of the individual portion, have different overall processing times in a microwave oven.
Thus, for example, in a restaurant which may possess a plurality of microwave ovens, where people at one table order foods requiring various processing times, an operator has to be on the lookout to remove appropriate portions of food from respective ovens as they become ready. This is inconvenient for the operator and uneconomic of his time, and it is also inconvenient for the customers who will either receive their portions of food at different times, or if they all receive their portions of food at the same time, then some of the portions will be cold.
In order to have the different portions of food become ready at the same time, which would be most convenient for the operator and most economic of his time, and which would provide the best service to the customer, the individual ovens would have to be turned on at appropriately different times, i.e. the oven containing the portion with the longest processing time would have to be turned on first, and the ovens containing portions with lesser processing times would have to be turned on at appropriate intervals later. This again is inconvenient for the operator and uneconomic of his time.
Note that this problem would be mitigated, but not solved, if the operator calculated the point in time for each oven at which it should be turned on so that the processing for all of the ovens in the plurality would terminate at the same moment; but, apart from the inconvenience of, and cost of time in, making the aforesaid calculation, the operator would still have to remind himself when to turn on each oven, and he would still have to return to the scene at each point in time in order to turn each oven on. Hence the problem of inconvenience for the operator and the cost of his time would remain. Moreover, owing to human error, ovens would probably not be turned on at the right times, and the portions of food would be ready at the wrong times, resulting in loss of customer satisfaction, either because of the delay, if the oven in question had been turned on too late, or because of the portion of food being cold, if the oven had been turned on too soon.
It is also known in the art for the electronic controls on microwave ovens to include a time-of-day feature, one of the benefits being that the digital display usually accompanying the electronic control can also be used, when the oven is not occupied, to display the time of day, i.e. to serve as a clock. It is further known to include the additional feature that the process in the oven be automatically turned on in such a way as to end at a set time of the day (a feature somewhat comparable to a similar feature that has existed for some years on conventional electric or gas ranges).
If a plurality of microwave ovens were each equipped with the time-of-day clock and also with the additional feature of automatically being turned on in such a way as to end at a set time of the day, then it would be possible to mitigate the problem described earlier, as follows: First, it would be necessary to ensure that the time-of-day clock settings for all the ovens in the plurality were synchronized. Secondly, the operator would have to calculate the expected time in the day when the portion of food with the longest processing time was expected to finish. Thirdly, the operator would then have to enter that same completion time of day for each of the ovens, along with the individual instructions for processing.
This method of using a plurality of microwave ovens would appear to come closest to a solution to the problem as it eliminates the need for the operator to make repeated visits to the plurality of ovens in order to turn each one on at the appropriate time. However, it leaves him with the problem of selecting the oven with the longest processing time, which is not necessarily easy to do as the more sophisticated processing programs involve a consecutive series of power settings, each with its own length of processing time; and it also leaves the operator with the problem of calculating the time of day of expected completion of the longest program.
This is relatively error-fraught as minutes and seconds are in sets of sixty, rather than being based on the generally-used decimal principle, and the hours part of the time is duodecimal rather than decimal, being furthermore burdened either with the need to watch for A.M. and P.M. or, alternatively, the unfamiliar 24-hour clock convention. The probability of error is magnified in the two most common situations of use of microwave processing of food, namely, in the food-service industry which relies heavily on employees who are young, inexperienced, unskilled, and lack the positive attitude to work that enhances accuracy; and in the home, where experience in the marketplace has shown that housewives have a negative attitude to microwave ovens with controls that appear to be complicated.
The probability of error is further magnified when it is borne in mind that both the operator in the restaurant and the housewife in the kitchen are frequently interrupted in the course of their duties and may find that they have not had the chance to turn on all of the ovens after starting one of them; or that the time of day for completion which had been calculated before the interruption needs to be calculated again.
Besides the problem of managing a plurality of ovens so that different types of portions of food can be ready to serve at the same time, there is also the problem that a plurality of microwave ovens is costly, insofar as the electronic (or, possibly, in some models, the electromechanical) controls are repeated for each oven. This problem of cost, which exists wherever it is desired to process more than one type of food at the same time, is particularly onerous in the domestic situation where it is very uncommon for the housewife to possess more than one microwave oven. In this situation, the user must either restrict her use of the microwave oven to just one food at a time, or (and this is a frequent recommendation by the manufacturers of microwave ovens) she must carefully arrange the various types of foods according to their type and acccording to their mass, combined, in such a way that the complete contents of the oven are ready at one time. Such a careful arrangement takes a degree of skill and experience that is not possessed by many users or which potential users are often unwilling to acquire.
The problem of cost, while most readily described in terms of the domestic user, also exists in the food-service trade, where, for example, a restaurant may possess two or three microwave ovens, but cannot afford to own, say, thirty microwave ovens when each one requires separate controls and, hence, cannot apply microwave processing on a scale that may otherwise be desirable.
While the cost of the controls that are repeated in each unit in a plurality of ovens is a problem, there are also other elements such as the digital displays and the keyboard or equivalent input devices, and the physical outside housings which protect five of the six sides of the rectangular cubic shape of each oven and which are redundant to the extent to which a plurality of ovens can be ranged alongside each other, horizontally, and/or stacked on top of each other, vertically; all of which represent costs, repeated for each oven in a plurality, which discourage the acquisition of a plurality of microwave ovens or which prevent the acquisition of larger numbers of microwave ovens where such larger numbers would otherwise be warranted.
The sets of hardware, such as hinges, handles, and mouldings, associated with the individual doors of the ovens, also represent a cost which discourages the acquisition of a plurality, or larger pluralities, of microwave ovens. In the case of doors, the fact that, when a plurality of ovens are used together to process foods that are to be served at the same time, the operator must open the door to each oven separately, is also inconvenient.
All of the foregoing drawbacks in the prior art,cumulatively, result in one final drawback insofar as the domestic and the small food-service, as opposed to the larger food-service, user is concerned, namely the lack of small microwave ovens for use in the home or small restaurant. This lack exists, not because the prior art stands in the way of such smaller ovens (indeed, there are microwave ovens that are smaller than the common domestic models, available to the food-service trade), but because the high cost and inconvenience of trying to use a plurality of microwave ovens in the prior art cause the potential market to be too small to justify their production; which also produces an additional drawback in that even the housewife or owner of a small restaurant who is willing to pay the price for a plurality of microwave ovens and who is willing to overlook the inconveniences enumerated above, may not be able to spare the space in the kitchen for the plurality of ovens; for the manufacturers of those ovens must take a large size of cavity as the lowest common denominator of execution of the prior art; generally big enough to accommodate a medium-to-large size turkey, but no smaller. The attraction of such a common denominator is obviously great, witness the fact that domestic microwave ovens manufactured in several countries are all almost the same size.